code: def test_forward_cpu(self):
      self.check_forward(self.x, self.t, self.W, self.samples)
  
file_path: chainer/tests/chainer_tests/functions_tests/loss_tests/test_black_out.py
imports: import unittest
  import numpy
  import chainer
  from chainer.backends import cuda
  from chainer import functions
  from chainer import gradient_check
  from chainer import testing
  from chainer.testing import attr
  from chainer.testing import condition
label_desc: Use image node_id 3 for calling the TestBlackOut obj's underlying member method code with example usage: obj.test_forward_cpu() without return types